Study on the therapeutic effects of Qinghuang ointment in a mouse model of imiquimod-in-duced psoriasis and its underlying mechanisms

LIU Dan; GONG Canyi; XU Jing; WEN Si; WU Zhaoji; HE Jiao; XIA Bijun

doi:10.3969/j.issn.1674-8468.2025.05.002

Abstract：Objective To study the therapeutic effects of Qinghuang ointment on psoriasis and its underlying mechanisms in a mouse model.Methods Twenty-five mice were randomly as-signed to the following groups:blank control group,model group,Qinghuang ointment group,positive control group,and vehicle control group,with 5 mice per group.Except for the blank controls,all mice were treated topically with 5％imiquimod cream once daily for seven days to es-tablish a psoriasis model.The Qinghuang ointment group and the positive control group were topi-cally treated with Qinghuang ointment and clobetasol propionate urea cream,respectively,for 7 days,while mice treated with vehicle alone served as vehicle controls.The mice were observed daily for changes in erythema,scaling,and skin thickness on their backs,and PASI scores were recorded.On day 8,the stratum corneum hydration(SC),transepidermal water loss rates(TEWL),and pH value on the back skin were measured.Hematoxylin and eosin(HE)staining was performed to examine histopathological changes in the back skin.The spleen index was calcu-lated.The mRNA expression levels of cytokines,TNF-α,IL-6,IL-17,IL-23 and IFN-γ,in skin tissues were measured by quantitative real-time PCR(qPCR).Results Starting from day 2,all groups except the blank control group began to develop erythema,scaling,and thickened skin le-sions on their backs.The severity in the Qinghuang ointment group was reduced compared to the model group.The histopathological examination showed that compared to the model group,the Qinghuang ointment group reduced epidermal thickening,and decreased hyperkeratosis,parakera-tosis,and inflammatory cells.Compared with the model and vehicle groups,mice in the Qing-huang ointment group showed significant reductions in PASI scores,reaching levels comparable to those in the positive control group.Moreover,Qinghuang ointment increased SC,decreased TEWL and the spleen index,while downregulating the mRNA expression levels of TNF-α,IL-6,IL-17,and IL-23(all P＜0.05 vs.model group).There were no significant differences in the expression levels of TNF-α、IL-17,and IL-23 mRNA between the positive group and the Qing-huang ointment group.There were no significant differences in either pH(F=1.22,P=0.335)or IFN-γ mRNA expression(F=2.49,P=0.088)among the five groups.Conclusions Qing-huang ointment has a good therapeutic effect on psoriasis in mice,and its mechanism may be relat-ed to improving skin barrier function,modulating immune responses,and inhibiting Th1/Th 17 cell-mediated inflammatory response.